Background References Conclusion Figure 1 Observed and Predicted Blood Lead Using 18 % Aggregate Bioavailability for Soil and Dust

a century of mining and smelting at Bunker Hill contaminated soil and interior dust with lead and other metals. Following closure of the smelter in 1981, lead in soil and dust were identified as primary exposure pathways for children living on the Bunker Hill Site in the Silver Valley, Idaho. Scientific approach to resolving the issue- Soil and dust have been sampled annually as contaminated soil was replaced with clean soil at schools, parks, businesses, and approximately 2,200 residences. Annual voluntary blood lead screening has recruited over 50 % of exposed children every year from 1988 through 2002. Blood lead levels have decreased as soil and dust lead levels have declined as the soil cleanup progressed. Bioavailability was estimated by comparing lead uptake from over 5,000 blood lead measurements paired with estimates of lead intake from thousands of soil and dust measurements. Lead intakes were estimated using a range of assumptions of the relative importance of lead levels in 1) house dust, 2) residential soil from a child's own yard, 3) soil from neighboring yards, and 4) the mean concentration from all yards in a town. The impact of various exposure assumptions on the estimated intake was minimal because of correlations among these measures of exposure